1. Field of the Invention
The invention relates to a method and a repair apparatus for repairing short circuits between first electrodes and one or more second electrodes of a multi-color organic light-emitting display device containing a color-converting filter section. The invention can be used in the field of multi-color organic light-emitting display devices having color-converting filters.
2. Prior Art
Organic light-emitting devices have characteristics that low-voltage driving is possible and visibility is good due to being self-luminescent, and hence research into making organic light-emitting devices fit for practical use has been carried out vigorously (see Appl. Phys. Lett., 51, 913 (1987)). As such organic light-emitting devices, ones that comprise a substrate, first electrodes, an organic light-emitting layer comprising a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer or the like, and one or more second electrodes are known, both in the case of an active matrix driving type (one second electrode) and in the case of a passive matrix driving type (plural second electrodes).
With such an organic light-emitting device, defects caused by short-circuiting between the first electrodes and the second electrode or electrodes may occur. The occurrence of such defects is a large factor in the yield being reduced.
Pixels where there is an electrical short circuit will not light up due to the inter-electrode potential required for light emission no longer being obtained, and hence these pixels will become display defects, that is, black spots in the display. Moreover, these pixels cause various other image quality defects when displaying an image. For example, well-known such image quality defects are a data line including a short-circuited pixel being lit continuously in the form of a bright line, the whole of an address line containing a short-circuited pixel becoming dark, and so on.
Methods for repairing such short circuits between such first and second electrodes include, for example, a method in which repair is carried out by partially destroying the short-circuited electrodes using a laser (a laser-based repair method) (see, for example, Japanese Patent Application Laid-open No. 2002-260857, Japanese Patent Application Laid-open No. 2001-118684, Japanese Patent Application Laid-open No. 2000-208252, Japanese Patent Application Laid-open No. 2000-195677, and Japanese Patent Application Laid-open No. H5-340905). All of these patent documents disclose the repair of an organic light-emitting display device that does not have color-converting filters using a laser-based repair method.
In recent years, the development of multi-color organic light-emitting display devices in which color-converting filters are added as constituent elements to an organic light-emitting device as described above, has been carried out vigorously. With multi-color organic light-emitting display devices having color-converting filters, again reduction in image quality due to short-circuiting between electrodes in the organic light-emitting device section has been a problem. Such short-circuiting between electrodes may have to be repaired in a state in which the color-converting filters have already been provided on the multi-color organic light-emitting display device.
Repairing short circuits between first electrodes and one or more second electrodes of multi-color organic light-emitting display devices is important for preventing a drop in yield. However, there is a problem in the case of applying the laser-based repair method to a multi-color organic light-emitting display device. That is, because the multi-color organic light-emitting display device has color-converting filters, the laser irradiation cannot be carried out from the side where they are present. This is due to the fact that if the laser-based repair method is used to repair short-circuiting between electrodes in a multi-color organic light-emitting display device having color-converting filters from the side of the color-converting filters, the laser irradiation will damage a passivation layer or color-converting filter layers in the color-converting filter section. In particular, there is a problem that if the passivation layer is damaged, then moisture contained in the color-converting filter layers will diffuse out, and damage the organic light-emitting device, resulting in dark spots. This problem is particularly marked, for example, with a bottom emission type, passive matrix type, multi-color organic light-emitting display device in which the organic light-emitting layer is formed after the color-converting filters have been formed. Furthermore, with a multi-color organic light-emitting display device of this type, if it is decided to carry out the laser irradiation from the side of the organic light-emitting layer, i.e. the side opposite to the side of the color-converting filters, after sealing has been carried out, then there will be a problem that the choice of sealing member, drying agent and so on will be restricted. Moreover, there are calls for a repair method having a broad range of application that can also be applied to multi-color organic light-emitting display devices of other types.